Synlett 2020; 31(12): 1158-1162
DOI: 10.1055/s-0040-1707111
letter
© Georg Thieme Verlag Stuttgart · New York

Intramolecular Cyclization of Vinyldiazoacetates as a Versatile Route to Substituted Pyrazoles

Denis Drikermann
a   Friedrich-Schiller-University Jena, Institute of Organic and Macromolecular Chemistry, Humboldtstraße 10, 07743 Jena, Germany   Email: ivan.vilotijevic@uni-jena.de
,
Valerie Kerndl
a   Friedrich-Schiller-University Jena, Institute of Organic and Macromolecular Chemistry, Humboldtstraße 10, 07743 Jena, Germany   Email: ivan.vilotijevic@uni-jena.de
,
Helmar Görls
b   Friedrich-Schiller-University Jena, Institute of Inorganic and Analytical Chemistry, Humboldtstraße 8, 07743 Jena, Germany
,
a   Friedrich-Schiller-University Jena, Institute of Organic and Macromolecular Chemistry, Humboldtstraße 10, 07743 Jena, Germany   Email: ivan.vilotijevic@uni-jena.de
› Author Affiliations
This research was funded by the Carl-Zeiss-Stiftung (endowed professorship to I.V.), Friedrich-Schiller-Universität Jena, the Ernst Ludwig Ehrlich Foundation (graduate fellowship to D.D.) and the State of Thuringia (2015 FGI0021) co-supported by the European Regional Development Fund (ERDF).
Further Information

Publication History

Received: 13 March 2020

Accepted after revision: 14 April 2020

Publication Date:
05 May 2020 (online)


In memory of Prof. Dr. Ludwig Knorr, professor at Friedrich-Schiller-University Jena (1889–1921)

Abstract

Vinyldiazo compounds undergo a thermal electrocyclization to form pyrazoles in yields of up to 95%. The reactions are operationally simple, use readily available starting materials, require no intervention of a catalyst, and enable the synthesis of mono-, di- and tri-substituted pyrazoles. With the ability to produce highly substituted pyrazoles and the flexibility in installing various types of substituents, this method constitutes a new entry to this valuable heterocyclic scaffold and may be of interest to all branches of the chemical industry.

Supporting Information